How to Weld Thin Metal: A Beginner’s Guide

When most people think about welding, they think about powerful machines welding massive chunks of metal. However, welding is also a useful tool for welding thin, delicate pieces of metal. There are a few reasons why you may want to weld thin metal. Maybe you’re working in a factory that is using thin sheet metal, or you are trying to make welding art at home. 

Welding thin metal comes with its own unique challenges. You can get around them by adjusting the welding angle, shielding gas, and other aspects of the welding job.

Whatever the reason you are tackling this challenge, here are the ways to successfully weld thin metal.

Why Is Welding Thin Metal Different?

If welding is a versatile, universal technique, you may be wondering why you need a separate guide just to weld thin metals. These are metals just like any other, right? 

However, there are a few reasons why welding thin metas is different from welding thicker substances. Thin metal is more sensitive to heat. Welding works by melting the metal you are working with just enough to create material for a seam. With thin metals, it’s a lot easier to melt the metal all the way through if you’re not careful and don’t have enough control over the heat of your welding machine. That is called burn-through.

Many welders compensate for this by lowering the heat, but the joints will not be supple enough if you don’t use enough heat. Striking the balance between just enough heat and not enough is a delicate task, especially for beginners.

That is why welding thinner metals such as aluminum is much harder than welding thicker materials.

weld thin metal

What Is the Best Welding Method for Thin Metals?

There are several welding methods out there, including: 

  • MIG welding
  • TIG welding
  • Stick welding

Of these methods, the best one for welding thin metals is MIG welding. This is the most common type of welding that people in manufacturing use for welding sheet metals, which are thin pieces of metal. Plus, you can pulse when using MIG welding, lessening your burn-through risk.

Although TIG welding was designed for very thick pieces of metal, it is also a good choice for welding thin metals. TIG welding is more precise and gives you more control over the heat application. However, it is much harder to use for amateurs.

When working with very thin metals, skip stick welding. This method gives you the least control over the heat application and is most likely to result in burn-throughs, splattering, and excessive slag formation.

How to MIG Weld Thin Metals

MIG welding is the most common technique welders use for thin metals. Here are the steps you need to take for this process.

1. Choose the Right Shielding Gas

MIG welding works in tandem with the shielding gas, which prevents the weld from oxidizing. The shielding gas also affects the weld bead’s appearance. For thin metals, you want a weld bead that won’t produce a lot of spatter when it appears.

Use shielding gases that have high argon concentrations.

2. Choose the Right Filler Metal

The filler metal is the metal that melts into the weld and fills the gap between the two pieces. MIG welding automates feeding the filler, which makes your life as a welder easier. The material doesn’t matter as much as the form of the filler metal.

Ensure you use very thin wires when working with reedy, thin sheet metal.

3. Adjust Your Torch Angle

Changing the torch angle when MIG welding goes a long way to preventing burn-throughs. Make sure that you adjust the angle to shorten the distance between the tip and the metal, no matter the welding position you are working in. This will make the arc more stable, giving you more control over the weld and lessening the chance of burn-through.

4. Try Pulsing

Besides your regular MIG welding technique, you can also try pulsing when welding thin metals. When you pulse metals, you heat a small portion of the plates you are trying to join, then let the weld pool completely before filling in the joint. Although pulsing requires practice to master, it gives you more control over the energy output.

How to TIG Weld Thin Metals

Although TIG welding was designed for thicker materials, you can use it to weld thin metals thanks to the extra control you get over the energy output. Here are the steps to follow.

1. Adjust to the Correct Amperage Settings

The first thing you need to do when TIG welding thin metals is to adjust the amperage settings. Lower the power setting and switch out the anodes to smaller ones. This lessens the energy output. You don’t need as much energy to melt thin metals anyway, and this way, you prevent burn-through. TIG welding lets you control the heat as you weld with a foot pedal, so take advantage of that.

2. Pick the Right Filler Metal (and Add It Properly)

TIG welding uses tungsten anodes to create the arc. For thin metals, experts recommend 0.020 and 0.040 thoriated anodes. Thoriated tungsten is alloyed with the metal thorium, which gives the anode more current distribution.

3. Use an Even, Fast Distribution

When TIG welding thin metals, avoid concentrating the heat in one place for too long. Stitch welding is the best technique, which uses a skip technique to apply a series of welds along a seam. This prevents you from applying too much heat in one place.

Final Thoughts

Welding thin metal is sometimes harder than welding massive chunks of metal because the likelihood of burning through and damaging the base metal is much higher. For this welding challenge, use a welding method that gives you a lot of control, such as MIG or TIG welding, make sure you have the right electrodes and shielding gas, and adjust your technique.